It is necessary that the wire protocols distinguish between
existence and non-existence of resources in a standard manner
(NXDOMAIN in this case) in order to give the client the choice of
how to handle non-existence.
[ on dns not the best choice for authoritative non-existence ]
it's hard to imagine that there's a better oracle than DNS to ask about
the (non-) existence of a DNS name.
now to assume that the DNS name is bound to anything in particular,
like a host, or a particular business concern, that would be a stretch.